/**
 * 1. Write an object Conversions with methods inchesToCentimeters, gallonsToLiters, and milesToKilometers.
 */
scala> object Conversions {
     |   def inchesToCentimeters(inches: Double): Double = 2.54 * inches
     |   def gallonsToLiters(gallons: Double): Double = 3.78541 * gallons
     |   def milesToKilometers(miles: Double): Double = 1.61 * miles
     | }
defined object Conversions

scala> Conversions.inchesToCentimeters(10)
res56: Double = 25.4

scala> Conversions.gallonsToLiters(1)
res57: Double = 3.78541

scala> Conversions.milesToKilometers(7)
res58: Double = 11.270000000000001

/**
 * 2. The preceding problem wasn’t very object-oriented. Provide a general superclass UnitConversion and define objects InchesToCentimeters, 
 * GallonsToLiters, and MilesToKilometers that extend it.
 */
scala> abstract class UnitConversion {
     |   def convert(input: Double): Double
     | }
defined class UnitConversion

scala> object InchesToCentimeters extends UnitConversion {
     |   def convert(input: Double) = 2.54 * input
     |   def apply(input: Double) = convert(input)
     | }
defined object InchesToCentimeters

scala> InchesToCentimeters(1)
res59: Double = 2.54

scala> InchesToCentimeters(10)
res60: Double = 25.4

/**
 * 3. Define an Origin object that extends java.awt.Point. 
 * Why is this not actually a good idea? (Have a close look at the methods of the Point class.)
 */
 // Not a good idea since it has setXXX methods and in singleton since everybody shares, anyone can
 // change value causing trouble
 
 /**
  * 4. Define a Point class with a companion object so that you can construct 
  * Point instances as Point(3, 4), without using new.
  */
scala> :paste
// Entering paste mode (ctrl-D to finish)

object Point {
  def apply(x: Int, y: Int) = new Point(x,y)
}

class Point private(x:Int, y: Int) {
  override def toString = s"New Point Created (${x}, ${y}))"
}

// Exiting paste mode, now interpreting.

defined object Point
defined class Point

scala> Point(3,4)
res0: Point = New Point Created (3, 4))

/**
 * 5. Write a Scala application, using the App trait, that prints the command-line arguments 
 * in reverse order, separated by spaces. For example, scala Reverse Hello World should print World Hello.”
 */
// Open a new file called MyApp.scala and paste the following contents
object MyApp extends App {
 if(args.length < 1) println("Provide enough arguments to print")
 println(args.reverse.mkString(" "))
}

$ scalac MyApp.scala

$ scala MyApp Hello World Scala
Scala World Hello

$ scala MyApp
Provide enough arguments to print

// Not attempting 6,7,8 (Enumeration)